1. Field of the Invention
The present invention relates to the field of synthetic resins, particularly to resins having a network structure, and more particularly to resins having urea or urethane linkages.
2. Description of the Related Art
Polymeric compositions having a network structure may be prepared using building block compounds which react to link with three or more other building blocks in the composition. Such networked polymers may contain very high molecular weight molecules, and in some cases an entire bulk sample represents essentially a single molecule, with every atom covalently linked to the other atoms in the composition.
An example of such a polymeric composition can be seen in Randrianantoandro et al., xe2x80x9cViscoelastic Relaxation of Polyurethane at Different Stages of the Gel Formation. 1. Glass Transition Dynamics, xe2x80x9cMacromolecules, 1997, 30, 5893-5896. This paper describes polyurethanes made by condensing a polyoxypropylene triol with hexamethylene diisocyanate. Here, the polyoxypropylene triol is a polypropylene oxide adduct of trimethylol propane, and is trifunctional in that the triol has three hydroxy groups to react with the isocyanate groups of the diisocyanate. The paper also describes polyurethanes made from the further addition of a polypropylene oxide diol or from the further addition of phenyl-2-propanol, a monoalcohol.
Many different physical parameters are of interest in assessing polymer performance, including glass transition temperature, modulus as a function of frequency, and creep compliance. Often it is difficult to achieve desirable values of two or more of these parameters in a single polymer composition, and there is therefore a need for new compositions with novel properties. For example, in polyurethanes made from trifunctional hydroxy compounds (triols), difunctional hydroxy compounds (diols) and diisocyanates, compositions which are very soft, that is, which have a low value of rubbery modulus, tend to lose structural integrity.
It is therefore an object of the present invention to provide a novel networked polymer.
A further object of the invention is to provide a polymer having novel polymer performance.
A yet further object of the invention is to provide a polymer having low creep and low rubbery modulus.
These and other objects are achieved by the present invention, which includes novel polymer compositions, methods of making the compositions, and methods of using the compositions.
An exemplary composition of the invention is made by copolymerization of a trifunctional amine or hydroxy compound, a monofunctional amine or hydroxy compound and a diisocyanate compound. The resulting compositions may be used in a variety of applications, and may have combinations of properties which are generally difficult to achieve.